The operation of traffic control signals has become increasingly sophisticated. Traffic signals can include such things as traffic control lights, crosswalk lights and the like. Many traffic signals are now controlled by computers to time the operations of the various signals they provide such as green, yellow and red lights. The timing of such operations can be determined by the time of day or night, weather conditions, traffic conditions, overrides from emergency vehicles, pedestrians and the like. Such changes in operations can be highly variable and relatively instantaneous.
One example of traffic signal control is the crosswalk override. In this case, a pedestrian can activate a signal device, such as a pushbutton switch, to indicate to the traffic signal controller that they would like to cross the street. The computer, in accordance with preprogrammed instructions, can then turn a traffic light from green to red and turn on a crosswalk light indicating that the pedestrian can cross the street while the car traffic light is red. Such a system can be located at an intersection or an area of the road where there is no intersection but only a crosswalk.
Another form of traffic signal override can be located at an intersection that normally allows the major road to constantly have a green light. A minor road at the intersection can have a vehicle sensor that senses the presence of a vehicle at the intersection wishing to enter the major road. The minor road users encounter a normally red light which needs to change to green while the major road light needs to be changed to red. In accordance with preprogrammed instructions, the traffic signal, once it receives a signal from the minor road sensor, will change the lights so that the vehicle on the minor road can safely enter or cross the major road.
Traffic control thus results in people spending unproductive time waiting at traffic signals. It would be desirable to provide such people with useful information during a wait period. However, the presentation of such useful information needs to be timed appropriately to the operation of the traffic signal. This is desirable so that an entire message can be appropriately delivered to the people in a timely manner.
However, the elapsed time for displaying such information is a variable and occurs at different times of day. Thus, there is presented the problem of how to display information at a traffic signal in a useful manner.